The Lost World: Jurassic Park is a 1997 American science fiction action film, directed by Steven Spielberg from a screenplay by David Koepp. It is the second installment in the Jurassic Park franchise and the original Jurassic Park trilogy. A sequel to 1993's Jurassic Park, it is loosely based on Michael Crichton's 1995 novel The Lost World. Jeff Goldblum and Richard Attenborough reprise their roles from the original film with Julianne Moore, Pete Postlethwaite, and Arliss Howard joining the cast.

Four years after the original film, John Hammond (Attenborough) loses control of his company InGen to his nephew, Peter Ludlow (Howard). On the verge of bankruptcy, Ludlow intends to exploit dinosaurs from InGen's second island, Isla Sorna, with plans for a new dinosaur theme park in San Diego. Hammond sends a team, led by the eccentric chaos theorist and mathematician Ian Malcolm (Goldblum), to the island to document the dinosaurs and encourage non-interference, although the two groups eventually come into conflict.

After the original novel's release and the first film's success, fans pressured Crichton for a sequel. Following the book's publication in 1995, production began on a film sequel. Filming took place from September to December 1996, primarily in California, with a shoot in Kauai, Hawaii, where the first film was shot. The Lost World's plot and imagery is substantially darker than Jurassic Park. It makes more extensive use of CGI to depict the dinosaurs, along with life-sized animatronics.

The Lost World was among the most anticipated films of the year. It was accompanied by a $250 million marketing campaign, which included video games, comic books, and toys. Released on May 23, 1997, the film received mixed reviews from critics, who praised the visual effects but criticized the character development. Spielberg also expressed disappointment with the film, stating he had become increasingly disenchanted with it during production. It grossed $618.6 million worldwide, becoming the second-highest-grossing film of 1997. It was nominated for numerous awards, including an Academy Award nomination for Best Visual Effects. A sequel, Jurassic Park III, was released in 2001. Goldblum would later reprise his role as Malcolm in Jurassic World: Fallen Kingdom (2018) and Jurassic World Dominion (2022).